ANATOMICAL AND CLINICAL FEATURES OF THE CIRCLE OF WILLIS: VARIATIONS AND THEIR ROLE IN CEREBROVASCULAR DISORDERS

Minora Saliyeva

Authors

Minora Saliyeva Andijan branch of Kukand university Author

Keywords:

Circle of Willis, cerebral arteries, anatomical variation, cerebrovascular disease, ischemic stroke

Abstract

The Circle of Willis is a major arterial anastomotic network located at the base of the brain and plays an essential role in maintaining cerebral perfusion when blood flow through one of the principal cerebral arteries is reduced or interrupted. Although the classical configuration of the Circle of Willis is frequently described in anatomical textbooks, complete and symmetrical anatomy is not present in all individuals. Variations such as hypoplasia, aplasia, duplication, fenestration, fetal-type posterior cerebral artery, asymmetry, and incomplete arterial connections are common and may influence cerebral collateral circulation. The aim of this study was to analyze the anatomical variants of the Circle of Willis and evaluate their clinical significance in cerebrovascular disorders, including ischemic stroke, intracranial aneurysm, carotid artery stenosis, and cerebral hypoperfusion. A narrative literature review was conducted using anatomical, radiological, and clinical studies focusing on the morphology of the Circle of Willis, computed tomography angiography, magnetic resonance angiography, digital subtraction angiography, cerebrovascular disease, and cerebral collateral circulation. The available evidence indicates that complete classical anatomy is present only in a proportion of the population, while hypoplastic or absent communicating arteries are among the most frequent variations.

Downloads

Download data is not yet available.

References

1. Krabbe-Hartkamp M.J., van der Grond J., de Leeuw F.E., et al. Circle of Willis: morphologic variation on three-dimensional time-of-flight MR angiograms. Radiology. 1998;207(1):103–111.

2. Alpers B.J., Berry R.G., Paddison R.M. Anatomical studies of the Circle of Willis in normal brain. Archives of Neurology and Psychiatry. 1959;81:409–418.

3. Riggs H.E., Rupp C. Variation in form of Circle of Willis. The relation of the variations to collateral circulation: anatomic analysis. Archives of Neurology. 1963;8:8–14.

4. van Raamt A.F., Mali W.P.T.M., van Laar P.J., van der Graaf Y. The fetal variant of the Circle of Willis and its influence on the cerebral collateral circulation. Cerebrovascular Diseases. 2006;22(4):217–224.

5. Kapoor K., Singh B., Dewan L.I.J. Variations in the configuration of the Circle of Willis. Anatomical Science International. 2008;83:96–106.

6. Eftekhar B., Dadmehr M., Ansari S., Ghodsi M., Nazparvar B., Ketabchi E. Are the distributions of variations of Circle of Willis different in different populations? Results of an anatomical study and review of literature. BMC Neurology. 2006;6:22.

7. Papantchev V., Hristov S., Todorova D., et al. Some variations of the Circle of Willis, important for cerebral protection in aortic surgery—a study in Eastern Europeans. European Journal of Cardio-Thoracic Surgery. 2007;31(6):982–989.

8. Hendrikse J., Hartkamp M.J., Hillen B., Mali W.P.T.M., van der Grond J. Collateral ability of the Circle of Willis in patients with unilateral internal carotid artery occlusion: border zone infarcts and clinical symptoms. Stroke. 2001;32:2768–2773.

9. Liebeskind D.S. Collateral circulation. Stroke. 2003;34:2279–2284.

10. Chuang Y.M., Liu C.Y., Pan P.J., Lin C.P. Anterior cerebral artery A1 segment hypoplasia may contribute to A1 hypoplasia syndrome. European Neurology. 2007;57:208–211.

11. Klimek-Piotrowska W., Rybicka M., Wojnarska A., Wójtowicz A., Koziej M., Hołda M.K. A multitude of variations in the configuration of the Circle of Willis: an autopsy study. Anatomical Science International. 2016;91:325–333.

12. Iqbal S. A comprehensive study of the anatomical variations of the Circle of Willis in adult human brains. Journal of Clinical and Diagnostic Research. 2013;7(11):2423–2427.

13. Hendrikse J., van Raamt A.F., van der Graaf Y., Mali W.P.T.M., van der Grond J. Distribution of cerebral blood flow in the Circle of Willis. Radiology. 2005;235(1):184–189

14. Hartkamp M.J., van der Grond J., van Everdingen K.J., Hillen B., Mali W.P.T.M. Circle of Willis collateral flow investigated by magnetic resonance angiography. Stroke. 1999;30:2671–2678.

15. Hoksbergen A.W.J., Majoie C.B.L.M., Hulsmans F.J.H., Legemate D.A. Assessment of the collateral function of the Circle of Willis. Stroke. 2003;34:1239–1242.